Material application systems are commonly used for applying liquid and powder material to an object, part or other surface. Due to the wide variety of materials that can be applied, there is also a wide variety of spray nozzle assembly designs. A spray nozzle assembly is used generally to atomize and/or electrostatically charge material and to produce a desired spray pattern. The spray nozzle assembly typically includes a nozzle holder or adapter and a nozzle tip or orifice. The assembly may include other parts such as seals for example. The assembly is typically mounted on the spray end of a gun or dispenser using a retaining nut or other suitable device.
Some objects, for example, single open ended cans, require a controlled or directional spray pattern to optimize application of material to the surface of interest. A controlled spray pattern is any spray pattern that is produced with a non-uniform distribution of material about the central axis of the nozzle tip. Controlled spray patterns are needed in many applications in which it is desired to direct material in a particular manner at the surface being coated. One example of a controlled spray pattern is a directional spray pattern which is simply a spray pattern in which the material exits the nozzle tip in an asymmetrical pattern relative to the central axis of the nozzle tip. An asymmetrical pattern is a spray pattern that has a shape that is heavier on one side or skewed to one side with respect to the central axis of the nozzle tip. Controlled and directional spray patterns and the nozzle designs to produce them are well known in the art.
Because a controlled spray pattern is intentionally asymmetrical about the central axis of the nozzle and/or gun, it is often necessary for the operator to know the alignment of the nozzle prior to starting a spray operation. Typically this is achieved by the nozzle adapter having a marking or indicia thereon that visually indicates to the operator the heavy side of the spray nozzle. In some cases, shallow grooves have been provided for visual indication of the spray pattern orientation. These indicia, however, can be very small (such as about 0.125 inch) and can be difficult to see and can even become obscured by overspray of material onto the nozzle adapter.